Stroke-adjuster for direct-acting engines.



R. W. ALLERTON.

STROKE ADJUSTER FOR DIRECT ACTING ENGINES.

APPLICATION FILED AUG. 15, 1911.

1,142,789. V Patented June 15, 1915,

3 SHEETSSHEET 1.

wneaaas [Ewe/afar:

THE NORRIS PETERS CO., PHOTO-LITHQ, WASHINGTON, D1 01 R. W. ALLERTON.

STROKE ADJUSTER FOR DIRECT ACTING ENGlNES.

APPLICATION FILED AUG. 15. I911.

Patented June 15, 1915.

3 SHEETS$HEET 2.

ayne v 3 Wrzama; '1 a. fiwmwz w THE NORRIS PETERS ca. PHOTG-LITHQ, wAsHlNGmN. D. C.

R. W. ALLERTON.

STROKE ADJUSTER FOR DIRECTACTING ENGINES. I

' APPLICATION FILED AUG. 15. 1911.

1 ,142,789. Patented June 15, 1915.

THE No aR/s PETERS 6d,.m1om-uma, wnsmucmu. o. c.

*ornrnn sra'rns PATENT opin on.

ROBERT W. ALLERTON, OF SOUTH ORANGE, NEW JERSEY, ASSIGNOR T0 HENRY R. WORTHINGTON, A CORPORATION OF NEW JERSEY.

STROKE-ADJUSTER FOR DIRECT-ACTING ENGINES.

Specification of Letters Patent.

Patented June 15, 1915.

Application filed August 15,1911. Serial N 0. 644,169.

To all whom it may concern Be it known that I, ROBERT W. ALLERTON, a citizen of the United States, residing at South Orange, county of Essex, and State of New Jersey, have invented certain new and useful Improvements in Stroke-Adjusters for Direct-Acting Engines, fully described and represented in the following specification and the accompanying drawings, forming a part of the same.

The object of the present invention is to provide improved means for automatically adjusting or regulating the stroke in direct acting engines, so as to maintain a practically constant stroke of the engine under varying conditions.

The invention relates especially to that class of direct acting engines which are provided with one or more compensating cylinders and pistons which are supplied with a suitable motor fluid and are arranged to act in opposition to the main piston or pistons during the first part of the stroke of the pistons and in conjunction therewith during the last part of the stroke, but the invention includes also features applicable to direct acting engines employing other compensating devices or to engines of lower duty in which no compensating devices are employed.

The invention may be applied, also, to compensating engines employing an accumulator between the compensating cylinders and source of compensating pressure or to engines in which no such accumulator is employed, but certain specific features of the invention relate to such accumulators and the application of the invention to compensating engines will be described in connection with such a construction.

For a full understanding of the invention a detailed description of a compensating engine of the preferred form embodying all the features of the invention, and a noncompensating engine embodying the broader features of the invention, will now be given, reference being had to the accompanying drawings forming a part of this specification, and the features forming the invention then specifically pointed out in the claims.

In the drawings: Figure 1 is a diagrammatic side elevation of a vertical pumping engine embodying the invention in connection with compensating cylinders and an accumulator. Fig. 2 is a detail vertical sec tlon of the adjuster valve for regulating the compensating pressure and the cylinder and pistonrby which it is operated. Fig. 3 is a. cross section on the line 3 of Fig. 2. Fig- 4 is a detail section of one of the oil pumps operated by the cross head. Fig. 5 is a diagrammatic side elevation of a horizontal low duty pumping engine with the stroke adjuster arranged to control the cross exhaust. Fig. 6 is a partial diagrammatic plan view of the same with parts broken away to show the adjuster connections. Fig. 7 is a vertical section through the adjuster valve and hydraulic cylinder for shifting the cross exhaust valve on the line 7 of F ig. 8. Fi 8 is a detail section on the line 8' of Fig.

Referring now especially to the construction shown in Figs. 1 to 4, the engine and compensating system illustrated, is the same as shown in United States Letters Patent to Brown No. 846,005, dated March 5, 1907, and except for the stroke adjusting devices, operates in the same manner so that no detailed description of the construction or operation of the general system is required.

In the drawings, A is the steam cylinder, B the pump cylinder, C the force main, D the air chamber on the force main, E the engine cross head, F the compensating cylinders having their pistons connected to the cross head, G the accumulator connected on one side of the piston H to chamber D by pipe I, and transmitting pressure to the compensating cylinders F from its smaller piston K through pipe L, the effective pressure of the piston H, being adjusted by admitting compressed air from an air tank or back pressure tank M through pipe 10 to the underside of the piston H, and this pipe 10 being connected by pipe 11 controlled by cock 12 with the air chamber at the upper end ofthe accumulator G for the supply of air to the air tank as desired. The usual gage and blow off pipe 13 and safety valve 1 1 are shown.

All the construction thus far described is old and the same as shown in Letters Patent No. 846,005,, but may be of any other common or suitable form.

Referring now to the features added for the embodyment of the present invention, the compensating pressure is increased to lengthen the stroke, in case the stroke shortens, by permitting the escape of air from the back pressure system, and the compensating pressure is decreased to shorten the stroke, if the stroke lengthens, by admitting air from the air chamber to the back pressure system, the stroke adjuster thus operating to increase or decrease the pressure in the back pressure system to adjust the length of the stroke and maintain it substantially uniform in length. For this purpose a pipe 15 connects the back pressure system with a valve chamber 16 in which moves the adjuster valve a, shown as a semirotary valve, and this valve chamber 16 is connected by air supply pipe 17 with the pipe I and air chamber 1), and to atmosphere or suitable waste by waste pipe 18, the valve chamber 16 being provided with ports 1, 2, 3 for the respective pipes 15, 17, 18, and the valve a controlling these ports so as to connect air supply pipe 17 with pipe 15 for the supply of air to the back pressure system, or to connect pipe 15 with pipe 18 for escape of air from the back pressure system, as the valve is moved to one side or the other of its central normal position, and to close the pipe 15 to both the pipes 17, 18 in the central normal position of the valve as shown in Fig. 3.

The valve a is shifted by lever 19 on the valve stem 20, which lever 19 is operated to shift the valve through link 21 connected to plunger 22 in oil cylinder 23, the downward movement of the lever being aided by coil spring 24 so as to maintain a pressure on the valve tending to connect the back pressure pipe 15 to the waste pipe 18. The cylinder 23 has two ports, 1, 5, in the lower part and its upper part 1s connected by overflow pipe- 26 to the oil reservoir, and by pipe 27 to chamber 28, with which also connects port 5, and this chamber 28 connects through adjustable needle valve Z) to supply chamber 29 which connects with port 1 and with pipe 30, through which the bil is pumped into cylinder 23 to control plunger 22 and the adjustable valve a.

The supply of oil through pipe 30 and position of plunger 22 is controlled by pumps on the engine cradle operated by the cross head, so that more or less oil is pumped into cylinder 23 according as the stroke is longer or shorter than normal. The pipe'30 connects with pump cylinders 31 mounted on the engine cradle on opposite sides of the cross head E, and having pistons 32 operated from the cross head E through the piston stems 33 carrying end buffers 6 and spring pressed by springs 3 1, the buffers 6 being engaged by adjustable tappets 7 on opposite sides of the cross head. The cylinders 31 receive oil through inlet valves 0 from supply pipes 35 connecting with any suitable oil supply, and deliver oil to the pipe 30 through outlet valves d. The cylinders 31 are provided also with ports 8 connecting the inner ends of the cylinder with pipe 36 connecting with pipe 26 and to the oil reservoir or waste, so as to relieve any pressure that might be caused inside the pistons 32 by the leakage of oil past the pistons and assure the action of the springs 34 in returning pistons 32 after their engagement and operation by the tappets 7.

The operation of the construction will be understood from a brief description. On each stroke of the engine the tappets 7 strike the buffers 6 on the piston rods 33 and operate the pistons 32 to pump oil through the pipe 30, chamber 29 and port 1 to the cylinder 23 below plunger 22, some of this oil also passing through the needle valve '1) and pipe 27 to the cylinder 23 above the plunger 22. If the needle valve 6 were closed entirely all the oil pumped would pass to cylinder 23 below plunger 22, and raise the plunger until it had passed port 5, when the oil would by-pass through port 5 and pipe 27 to the upper part of the cylinder, and be discharged through overflow pipe 26, which has an open port extending to the top of the cylinder. In practice the needle valve 6 is open to such an extent as to get the normal stroke required by the relative amounts of oil passing through port -l and pipe 27 and the return of the plunger 22 in cylinder 23 maintaining the plunger 22 in such position as to close the port 1 of pipe 15, or to admit air from the air chamber through pipe 17 to pipe 15 and the back pressure system, if required for the normal stroke. If now the engine short strokes, the amount of oil pumped by the pistons 32 will decrease, and if the shortening of the stroke and decrease of oil pumped be sulficient, the plunger 22 will not be held up in cylinder 23, as some oil is being by-passed through valve 6, and the plunger will descend, shifting the valve a to the left in Fig. 3 so as to connect the back pressure pipe 15 to waste pipe 18 and lower the pressure in the back pressure system, thus increasing the effective compensating pressure to lengthen the stroke. @n the other hand, if the engine long-strokes, the pistons 32 are given a longer stroke in their cylinders 31, pumping more oil into the cylinder 23, and

as the bypass valve 6 permits the passage of only a certain amount of oil, the plunger 22 will rise and shift the valve (1 to the left in Fig. 3, to connect supply pipe 17 from the air chamber with pipe 15, so as to supply air to the back pressure system and increase the back pressure so as to decrease the effective compensating pressure and shorten the stroke.

The invention provides a very simple and eflicient stroke adjuster, by which a stroke of constant length within very narrow variations can be maintained with certainty, and the normal length of stroke readily varied by slight adjustments. This result is secured most economically, also, as there is no waste of air except in case of the need of correcting a short stroke, and there is no waste of oil as the oil is used over and over again. The adjuster apparatus, also, is very simple and not liable to get out of order, while affording a very close adjustment, a slight variation in the movement of the pistons 32by the cross head acting on the valve (4 through the plunger 22.

While the invention is especially intended for compensating engines, it is of value also as applied to non-compensating engines, and in such engines the stroke adjusting devices may be applied in many different ways so as to vary the total effective pressure upon the piston or pistons so as to secure the desired result, and either by varying the worring pressure behind the steam piston or by varying the cushioning pressure in front of the piston, or by both, as for instance, by shifting the cross exhaust valve in a duplex engine, or by controlling the cuton" valves or dash-relief valves as shown and described in connection with a speed governor in United States Letters Patent #742,948, dated November 3, 1903, and the devices through which the stroke adjuster acts may be varied widely. For purpose of illustration the stroke adjuster of the pres ent invention is shown as operating the cross exhaust valve of a duplex engine so as to increase or decrease the amount of exhaust steam passing from the high pressure cylinder of one side of the engine to the low pressure cylinder of the other, the action being such as to open the cross exhaust pipe and increase the total effective pressure to lengthen the stroke as the stroke of the engine shortens and gradually close the cross exhaust pipe to decrease the total efiective pressure, as the stroke lengthens.

Referring now to the construction shown in Figs. 5 to 8, the engine shown is a duplex pumping engine of the well-known Worthington type, in which N are the high pressure cylinders, O the low pressure cylinders, P the pump cylinders, Q the induction pipe through which steam is supplied to the high pressure cylinders, R the high pressure exhaust pipes, S the low pressure exhaust pipes, and T the cross exhaust pipe connecting the high pressureexhaust pipes R so as to exhaust directly from the high pressure cylinder on one side of the engine to the low pressure cylinder on the opposite side of the engine as the high pressure cylinders exhaust, which is about two thirds stroke of the piston in the low pressure cylinder on the opposite side, so that this cross exhaust acts on the piston in the low pressure cylinder during the latter part of its stroke, the action being the same on each side of the engine and the cross exhaust passing alternately in one direction or the other through the cross exhaust pipe T, as well known inthis class of engines. This cross exhaust pipe T is provided with a valve 6 the movement of which controls-the amount of cross exhaust, which valve may be constructed and arranged as shown in said Letters Patent #7 42,948, or in any suitable manner. This cross exhaust valve is controlled by the stroke adjusting devices-so as to vary the amount of cross exhaust to lengthen or shorten the stroke as required. The stroke adjusting devices are the same as in the construction of Figs. 1 to 4 down to and including the valve lever 19, and are operated from the cross heads U by the same devices and in the same manner as above described, so that the same references will be used for corresponding parts in Figs. 5 to 8, and only the parts operated by the valve lever 19 need be described further. The lever 19, instead of operating a valve that directly controls the engine pressure, operates through stem 40 and valve f in valve chamber 41 to control a hydraulic piston which in turn is connected to operate the cross exhaust valve. For this purpose valve chamber 41 is connected with a hydraulic supply pipe 42 and has ports 9 and it connecting with a hydraulic cylinder 43 above and below hydraulic piston 44, and port 5, which connects with waste pipe 45. The piston 44 is connected by its rod 46 with an arm on rock shaft 47 mounted in the engine cradle, and this rock shaft 47 is connected by link 48 with the stem of the cross exhaust valve 6, so that the movement of the piston 44 in one direction opens the cross exhaust valve and in the other direction closes the cross exhaust valve- The valve f is operated by oil plunger 22 and lever 19, so as to connect the pipe 42 with port 9 and waste pipe 45 with port 71, as shown in Fig. 8, for moving the piston 44 downward, or by shifting to the left in Fig. 8 to connect supply pipe 42 to port it and connect waste pipe 45 with I port 9 for moving the plston upward according to the length of the stroke and so as to secure the desired movement of the cross exhaust valve e to bring the stroke back to normal length. r

It will be understood that the invention is not to be limited to the exact form or construction of devices shown, but that these are illustrated only as a preferred form for the embodiment of the invention, and that many modifications may be made in the form and arrangement of the stroke adjusting devices and that the invention may be applied to many different types of direct acting engines. While the pumps operated by the erably used for the purpose of moving the plunger 22 and the adjuster valve, and such a construction is claimed specifically, other means controlled by the engine stroke may be used for shifting the adjuster valve, within the broader features of the invention as defined by the claims.

What I claim is 1. The combination with a direct acting engine, of a stroke adjuster including valve mechanism acting to admit and exhaust fluid to vary the eliective pressure on the engine piston or pistons, and means for controlling said valve mechanism by the length of the engine stroke.

2. The combination with a direct acting engine, of a stroke adjuster including valve mechanism acting to admit and exhaust fluid to vary the efiective pressure on the engine piston or pistons, a fluid controlled plunger for moving said valve, and means for controlling said plunger by the length of the engine stroke.

3. The combination with a direct acting engine, of a stroke adjuster including valve mechanism acting to admit and exhaust fluid to vary the effective pressure on the engine piston or pistons, a fluid controlled plunger for moving said valve, fluid pumping devices controlling said plunger, and means for actuating the pumping devices by the engine in accordance with the length of the engine stroke.

4. The combination with a direct acting engine having one or more compensating cylinders and pistons acting in opposition to the engine piston during the first part of the stroke and in conjunction therewith during the latter part of the stroke, of a stroke adjuster including valve mechanism acting to adm1t and exhaust fluid to vary the com pensatmg cylinder pressure, and means controlled by the length of the engine stroke for adjusting said valve mechanism.

5. The combination with a direct acting engine having one or more compensating cylinders and pistons acting in opposition to the engine piston during the first part of the stroke and in conjunction therewith during the latter part of the stroke, and means for applying pressure fluid in opposition to the working pressure for adjusting the compensating cylinder pressure, of a stroke adjuster including valve mechanism acting to admit and exhaust fluid to increase or decrease said opposing pressure, and means controlled by the length of the engine stroke for adjusting said valve mechanism.

6. The combination with a direct acting engine having one or more compensating cylinders and pistons acting in opposition to the engine piston during the first part of the stroke and in conjunction therewith during the latter part of the stroke, an accumulator through which said compensating cylinders derive their pressure, and connections for admitting fluid to said accumulator in opposition to the Working pressure and permitting the escape of fluid from the back pressure system, of a stroke adjuster including valve mechanism controlling said admission and escape of back pressure fluid, and means controlled by the length of the engine stroke for adjusting said valve mechanism to vary the back pressure in the accumulator.

In testimony whereof, I have hereunto set my hand, in the presence of two subscribing witnesses.

ROBERT W. ALLERTON.

Witnesses A. R. Tnonson, JAs. R. EHNENDORF.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of iatents, Washington, D. C. 

